Field of the Invention
The mammalian immune system has a matchless ability to produce molecules with specificity and avidity for a particular spatial and polar structure, as may be found with sequences of amino acids and sugars. For a long period of time, one was dependent upon producing antibodies employing the immune system in vivo. The resulting polycolonal antibodies demonstrated high specificity for a specific antigen, but could not discriminate between various sites on the antigen and, furthermore, were a mixture of antibodies of varying specificity and avidity. Thus, one observed the averaging over the entire composition and not the properties of a specific antibody.
With the seminal discovery of Milstein and Kohler, one can now produce homogeneous compositions of antibodies, by fusing a B-lymphocyte with a myeloma cell to produce a cell referred to as a hybridoma. For the most part, the use of this technology has been limited to mouse cells, where stable myeloma lines have served as fusion partners to provide stable hydridomas which can be produced with high efficiency and are capable of being maintained as productive entities over long periods of time. Higher organisms, particularly humans, have proven to be much more intractable in the developing fusion partners and hybridomas. However, in 1980, the first human fusion partner was reported by Drs. Olsson and Kaplan and since that time, an additional few human fusion partners have been reported. Nevertheless, the preparation of hybridomas by human-human crosses has remained difficult due to problems of efficiency in fusion, culturing the cells, and maintaining their productive capabilities. However, because of the many advantages of having human hybridomas which produce antibodies allogenic to a human host, particularly for in vivo applications, human hydbridomas remain of great interest. In other instances, even with the difficulties encountered with human-human crosses, the human hybridoma may be preferable to a heterogenic cross, where the resulting hybridoma may lose the genetic information for the monoclonal antibodies (MoAbs) after a number of passages.
One of the areas of interest for the use of monoclonal antibodies is in diagnosing and treating cancer. Monoclonal antibodies for these purposes desirably are specific for a particular type of cancer or subset of cancers, rather than being specific for a particular host cancer cell. It is therefore desirable to develop monoclonal antibodies which can be used in the diagnosis and treatment of human cancers.